fix clang-tidy (#18030)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18030
ghimport-source-id: d68781226eee923c90be862ef54693feef5f1c1a
Stack:
* **#18030 [jit] fix clang-tidy**
fix the following complaint
```
pytorch/torch/csrc/jit/ir.cpp:84:7: error: pass by value and use std::move [modernize-pass-by-value,-warnings-as-errors]
const std::string& delim = ", ")
^~~~~~~~~~~~~~~~~~
std::string
```
Reviewed By: shannonzhu
Differential Revision: D14466714
fbshipit-source-id: 195cba335ae656db28fc6230b9e56ad208c88c29
